Safety door chain



Dec. 27, 1960 A. E. MINTZ 2,966,053

' SAFETY DOOR CHAIN Filed Feb. 27, 1958 2 Sheets-Sheet 1 ALB ERTEM/NTZ31 BY ift; W

Dec. 27, 1960 A. E. MINTZ SAFETY DOOR CHAIN Filed Feb. 27, 1958 2Sheets-Sheet 2 INVENTOR. ALBERTE. M/wz United States Patent O SAFETYDOOR CHAIN Albert E. Mintz, 61-64 Saunders St., Rego Park 74, N.

Filed Feb. 27, 1958, Ser. No. 718,035

7 Claims. (CI. 70-93) This invention relates to safety chains for doorsand more particularly to safety chains which may be locked and unlockedfrom the outside by authorized persons as well as used in their normalmanner by persons on the inside.

Safety chains are widely used to permit partial opening of the door forventilation or to permit a person on the inside to observe and conversewith persons on the outside and yet keep the person on the outside fromforcing his way into the house or room. Safety chains are also used asauxiliary night latches and provide additional security to a wife whosehusband works late at night, is away on an overnight business trip or isout visiting an occasional sick friend. These chains require someone onthe inside to lock and unlock them.

A problem is presented, however, when the husband returns, since he mustawaken the wife to undo the safety chain to let him in. This can be ofconsiderable annoyance to the wife as well as possible embarrassment tothe husband because of the lateness of the hour or other circumstances.

The safety chain comprising the present invention is adapted to befastened to the door and door frame to permit partial opening of thedoor for use in the conventional manner. Additional means is providedfor attaching and detaching the chain by an authorized person from theoutside. One end of the chain is connected to a plug which may beinserted into a casing mounted on the door frame and snapped intolocking position. The other end of the chain is in removable engagementwith a standard chain bracket mounted on the door. A key may be insertedin a keyhole at the upper end of the plug to release it from its casingto free the chain and permit the door to be opened. The releasing of theplug may be accomplished from the exterior by opening the door withinthe limits prescribed by the chain and inserting the key in the keyhole.Likewise, upon leaving the house, the plug may be readily inserted intothe casing, snapped into locking position and the door then shut andfurther locked with existing locks as desired or left open with theopening of the door again restricted by the chain. This safety chaindoes not require modification or replacement of existing door locks orcomplicated installation. The average housewife can mount it for use inabout five minutes with a screwdriver and a few wood screws.

It is therefore an object of this invention to provide for a safety doorchain which may be locked and unlocked by persons inside the door andauthorized persons on the outside.

Another object is the provision of a key actuated lock for removing oneend of a safety door chain.

Another object is the provision of a safety door chain which may beunlocked from the outside by opening the door to the limit permitted bythe chain and detaching one end of the chain by operating a key actuatedlock which connects the chain to the door or door frame.

Another object is the provision of a cylinder type lock with keyactuated tumblers for use in locking and unlock- 2,966,053 Patented Dec.27, 1960 Figure 3 is a plan view of the plug part of the lock,

Figure 4 is a front elevation of a modified form of safety chain lock,

Figure 5 is a similar view but with the lock shown rotatedcounterclockwise ninety degrees,

Figure 6 is a partial section on the line 6-6 of Figure 4 with partsbroken away, and

Figure 7 is a vertical section on the line 77 of Figure 6.

Referring to Figure 1, there is shown a fragmentary portion of a door 10and door-frame 11. The door has a knob 12, and the usual door lockswhich are not shown in the drawing.

In the preferred embodiment of the invention a safety chain 13 is shownattached at one end 14 to the slide part 15 which engages a standardchain bracket 16 secured to the door 10. The length of the chain is suchthat with the other end 17 aflixed to the door frame 11, the slide apart 15 cannot be released from the bracket until the door issubstantially fully closed.

A lock 20 is shown for illustrative purposes as mounted on the doorframe 11. It consists of a rectangular latch casing 21, and a detachableplug 22 for insertion therein, the plug being attached to end 17 of thechain. As shown in Figure 3 the casing 21 has an oblong opening 23extending through it to receive plug 22. A hollow cylindrical boss 24projects rearwardly into an aperture in the central elevated part 25 ofa rectangular mounting plate 26, shown in Figure 1 as secured by screws27 to door frame 11. The outer end of boss 24 is shouldered and securedin place by upsetting it within an opening in a retaining plate 28 andbonded or welded to prevent separation thereform. A pin 29 projectsrearwardly from casing 21 and into an aligned hole 18 in part 25 toprevent the casing from pivota-lly moving about the axis of boss 24.

In assembly, plate 28 bears against the inner surface of the elevatedpart 25 of plate 26 with the opposing rear Wall of casing 21 contiguousthe outer wall of said part. Casing 21 is thus rigidly supported on thedoor frame with opening 23 vertically disposed for a purpose which willpresently appear.

The detachable plug 22 of the lock 29 is relatively long since itcontains a conventional cylinder lock 30 with key actuated tumblers asshown in Figure 6. Although this view partly in section, of plug 22illustrates its use in a reversed position with respect to the positionshown in Figure 2 it is identical structurally in both instances.

As viewed from its end plug 22 is of oblong configuration, as shown inFigure 3, and is adapted to fit snugly Within the oblong opening 23 ofcasing 21. A lug 31 is integrally formed at one end of plug 22 and isapertured to receive the end link 17 of the chain 13. A stop pin 32projects from one side of lug 31 sufficiently to engage the casing 21and limit the movement of the plug inwardly. Movement in an outward oropposite direction is normally opposed by a latch 33 mountedtransversely for reciprocal movement across the major width of plug 22,and so as to extend within the hollow boss 24 and prevent unauthorizedwithdrawal of plug 22.

Latch 33 is chamfered as at 34 so as to engage a similar inclinedsurface 35 formed at one end of opening 23 to depress the latch as thelug is inserted into the opening. As shown in Figure 6 spring 36 urgeslatch 33 outwardly, the latter being formed with a square shank 37 toprevent it from rotating in a correspondingly shaped opening 38 in plug22. At its outer end the latch is cylindrical to thus provide ashoulder, indicated in dotted .lines in Figure 6, serving to limit itsmovement outwardly under the urging of spring 36.

The cylinder part 40 of lock 30 is provided at its inner end with aspindle 41 which is offset from the axis of part 40 so as to lie in aplane eccentric thereto. Spindle 41 extends into a recess 42 in latch 33and engages a wall 43 thereof. Suificient clearance is provided betweenthe spindle and an opposite wall of the recess to allow the latch tosnap into the locked position shown in the drawings when plug 22 ispushed into the opening 23.

When the key 44 is inserted in the keyhole at the outer end of plug 22and the cooperating tumblers are thereby brought into proper alignmentin the conventional manner of locks of this character, a rotary movementof the key in either direction will rotate. cylinder 40 and cause itsspindle 41 to impinge wall 43 and retract the latch. Then after pushingdownwardly a short distance with the key held turned, the latch will befree of casing 21. and the key then may be Withdrawn. Plug 22 may thenbe pulled completely out of casing 21 by grasping the adjacent end ofchain 13, and the door can be fully opened.

It. will now be apparent that the releasing of plug 22 may beeasilyaccomplished from the exterior by opening the door within the limitsprescribed by the chain, and

then inserting the proper key in the conveniently located keyhole at theupper end of plug 22. Likewise, upon leaving the house, plug 22 may bereadily inserted from beneath the casing and snapped into a lockingposition so that the opening of the door will again be restricted by thechain.

Referring to the modification shown in Figures 4, 5, 6 and 7, thearrangement shown is such that plug 22 may be conveniently inserted atthe top of casing 21 with lug 31 uppermost. The construction in thismodified form 'ofthe invention differs from that shown in the otherfigures by the provision of an arcuate slot 45 cut through elevated part25 of plate 26 for. the reception of the pin 29. Casing 21 may thusswing about the axis of boss 24 through an angle of 90 degrees from theposition shown in Figure 4 to that of Figure 5, the engagement of thepin with opposite ends of the slot defining such positions.

Since the door, if shown, would beto the right of Figure just as it isin Figure 1, the end of plug 22 into which the key 44 is to be insertedto free chain 13, will also be more easily available from the exteriorof the door, the position of the key at that time being shown in dottedlines in Figure 5.

It will be understood that the invention is not to be considered aslimited to the use. of a slide and bracket at the other end of thechainsince the end 14 of the chain could be secured to the door in a fixedposition if desired. The use of the. slide and bracket, however,provides greater convenience for the householder by making it possibleto release that end of the chain from the interior in a conventionalmanner without necessitating the use of a key at this time. Also, ifdesired the casing could be secured instead to the door with the otherend of the chain fastened to the door frame.

While certain preferred embodiments of the invention have beenspecifically disclosed, it is understood that the invention isnotlimited, thereto as many variations will be readily'apparent to thoseskilled in the art and the I claim:

1. A safety chain and lock for loosely connecting a door with theadjacent door frame to limit movement of said door and which may bedisconnected from the side of the door and frame opposite to the side towhich said chain and lock are mounted, said safety chain and lockcom-prising a chain removably fastened to said door, a latch casingadapted to be secured to said door frame and having an opening therein,said opening having an axis parallel to the plane of said door frame, aplug for insertion in said casing opening, said plug being con nected toone end of said chain and having a keyhole therein, a spring-responsivelatch mounted for reciprocal movement transversely in said plug, saidcasing and said latch being adapted to cooperate so that said plug canbe snapped into locking engagement within said casing, a cylinderlockcarried by said plug including a rotatable cylinder and key-actuatedtumblers, a spindle projecting from the inner end of said cylinder andeccentric to the axis thereof, said spindle being adapted to retractsaid latch when said cylinder is rotated by a key in said keyhole tothereby unlock the plug to free the plug connected end of the chain fromsaid door frame.

2. A safety chain and lock for loosely connecting a door with theadjacent door frame comprising a chain fastened to the inside of saiddoor, a latch casing for attachment to said door frame and having anopening therein, a plug for insertion in said casing opening, said plugbeing connected to one end of said chainand having a keyhole, aspring-responsive latch mounted for reciprocal movement transversely insaid plug, said casing and said latch being adapted to cooperate sothatsaid plug. can be snapped into locking engagement with said casing, acylinder lock carried by said plug including a rotatable cylinder andkey-actuated tumblers, a spindle projecting from the inner end of saidcylinder eccentric to the axis thereof and adapted to retract said latchwhen said cylinder is actuated by a key in said keyhole, and unlock. theplug to free said one end of said chain, said casing having a bossprojecting rearwardly therefrom, a plate to which said boss is pivotallysecured constituting a bracket for operatively supporting said casing,means for limiting the rotary movement of said casing in each direction,whereby the plug may be inserted in the top of the casing when itsopening is vertically aligned and a key may be inserted in the keyholeof the plug when said opening is horizontally aligned, said chain beingsufliciently long to permit opening of said door wide enough to permitinsertion and withdrawal of said plug from said casing by a personoutside the door. 7

3. A safety door chain for mounting on one side of a door and a wallmounted lock, said lock comprising two separable parts, one of saidparts being a wall mountable casing, said casing'having an openingtherein whose axisis parallel to the wall upon which said casing ismounted, the other of said parts comprising a plug for. insertion insaidpcasing, opening, a'spring-responsive latch mounted for reciprocalmovement'transversely in said plug, to provide locking engagement withsaid casing, means on said casing to receive said latch to preventwithdrawal of said plug, a cylinder" lock carried by'the plug. includinga rotatable; cylinder and key-actuated tumblers, a spindle projectingfrom the innerend of the cylinder of said lock eccentric to the axisabout which it rotates and adapted to retract said latch from itslocking position when said cylinder is rotated by a key whereby saidcasing and plug may be unlocked and separated from each other,.saidpluggbeing connected to said door by said chain of such length asto permit insertion of said key into said lock from the other side ofsaid door.

.4. A safety door chain comprising a chain with releasable means forattachment to the inside. of a door, a locking plug connected thereto, acasing with means forattachment to a door frame, said. casing having anopening therein with an axis parallel to the plane of said door framefor receiving said plug, said plug having latching means thereon forengagement with and receivable by said casing to prevent withdrawal ofsaid plug, and means insertable into said plug for releasing saidlatching means to permit withdrawal of said plug, said chain being ofsuch length as to permit the door to be partially opened to permitinsertion of said means from outside said door when said door, chain,plug and easing are connected.

5. A safety door chain as in claim 4, said casing attachment meanshaving an opening therein communicating with and at right angle to saidcasing opening, said latching means being spring urged into saidattachment means opening when said plug is inserted into said casingopening.

6. A safety door chain as in claim 4, said plug latching meanscomprising a latch, an opening in said plug receiving said latch, springmeans continually urging said latch outwardly, retaining means in saidcasing opening to receive said latch to prevent withdrawal of said plugfrom said casing, a key actuated rotatable cylinder in said plug, saidcylinder having means thereon engageable with said latch to remove saidlatch from engagement with said casing retaining means.

7. A safety door chain as in claim 4, said casing attachment meanscomprising a mounting plate, said casing being pivotally mounted on saidplate, a substantially arcuate slot in said plate, a pin on said casingreceived by said slot, said pin and slot thereby limiting pivotalmovement of said casing.

References Cited in the file of this patent UNITED STATES PATENTS1,136,357 Newman Apr. 20, 1915 2,002,260 Curl May 21, 1935 2,458,046Audet Jan. 4, 1949 2,696,100 Nehls Dec. 7, 1954 FOREIGN PATENTS 6,448Great Britain Mar. 15, 1912 11,532 Denmark Nov. 17, 1908 321,984 ItalyOct. 23, 1934 333,931 Germany Mar. 5, 1921

